立即刷新entitymanager工厂

Question

我的application-datasource.xmls在我的问题之下是我不想在这个 上下文文件中提供用户名和密码我想在运行时获取用户名和密码时用户登录但我不知道如何 来做到这一点。

<?xml version="1.0" encoding="UTF-8"?> 
    <beans xmlns="http://www.springframework.org/schema/beans" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop" 
    xmlns:tx="http://www.springframework.org/schema/tx" 
    xsi:schemaLocation=" 
    http://www.springframework.org/schema/beans http://www.springframework.org/schem...-beans-2.0.xsd 
    http://www.springframework.org/schema/aop http://www.springframework.org/schem...ng-aop-2.0.xsd 
    http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.0.xsd"> 

    <tx:annotation-driven /> 
    <!-- DataSource has been Lazily initialized, set lazy-init to false in production --> 

    <bean id="datasource" 
    class="com.mchange.v2.c3p0.ComboPooledDataSource" lazy-init="true" destroy-method="close"> 
    <!-- Tracker created for connection problem: https://sourceforge.net/tracker/?func=detail&aid=3176467&group_id=25357&atid=38369 0--> 
    <property name="driverClass" value="com.ibm.as400.access.AS400JDBCDriver" /> 
    <property name="jdbcUrl" value="${url}" /> 
    <!--<property name="user" value="${username}" /> 
    <property name="password" value="${password}" />--> 

    <!-- Pool Size Properties follow --> 
    <property name="minPoolSize" value="0"/> <!-- Minimum no. of pooled connections --> 
    <property name="initialPoolSize" value="1" /> <!-- Initial no. of pooled connections (>minimum)[optional] --> 
    <property name="maxPoolSize" value="2"/> <!-- Maximum no. of pooled connections (>minimum) --> 
    <property name="acquireIncrement" value="1"/> <!-- Connections to be added every time the need arises --> 

    <!-- Connection Establishment Strategy follows --> 
    <property name="acquireRetryAttempts" value="5" /> <!-- Retry Attempts on Database connection failure --> 
    <property name="acquireRetryDelay" value="1000"/> <!-- Milliseconds between re-tries --> 
    <property name="breakAfterAcquireFailure" value="true" /> <!-- Aggressively break DataSource on connection failure --> 

    <!-- Prepared Statement pooling --> 
    <property name="maxStatements" value="300"/> <!-- Value ~= maxPoolSize * no. of (frequently used)stored procedures --> 
    <property name= "maxStatementsPerConnection" value="15" /> <!-- Statement caching per connection for improved performance --> 

    <!-- Connection Age related settings --> 
    <property name="maxIdleTime" value="300" /> <!-- Seconds for a connection to remain idle before being closed --> 
    <property name="unreturnedConnectionTimeout" value="300" /> <!-- Wait for number of seconds for application to release a connection --> 

    <property name="idleConnectionTestPeriod" value="30000"/> <!-- Test for idle connections(In milliseconds) --> 
    <property name= "autoCommitOnClose" value="true" /> <!-- For ensuring all transactions to commit/rollback on close --> 
    <property name="debugUnreturnedConnectionStackTraces" value ="true" /> 
    <!-- Ignored overrides --> 

    <!-- Used for connection testing during startup --> 
    <!--property name="testConnectionOnCheckin" value="true" /--> <!-- Test for connection validity asynchronously --> 

    <!--property name="initialPoolSize" value="1" /--> <!-- Initial no. of pooled connections (>minimum)[optional] --> 
    <!--property name="idleConnectionTestPeriod" value="30000" /> In milliseconds(Overridden) --> 
    <!--property name="maxConnectionAge" value="1800" /--> <!-- Life in seconds for any connection(busy/idle) before being deleted --> 
    <!--property name="numHelperThreads" value="3" /--> <!-- Perform JDBC operations asynchronously --> 

    <bean id="entityManagerFactory" 
    class="org.springframework.orm.jpa.LocalContainerE ntityManagerFactoryBean"> 
    <property name="persistenceUnitName" value="persistence" /> 
    <property name="persistenceXmlLocation" value="classpathersistence.xml" /> 
    <property name="dataSource" ref="datasource" /> 
    <property name="loadTimeWeaver"> 
    <bean class="org.springframework.instrument.classloading .InstrumentationLoadTimeWeaver" /> 
    </property> 
    <property name="jpaVendorAdapter" ref="vendorAdapter" /> 
    </bean> 

    <bean id="vendorAdapter" 
    class="org.springframework.orm.jpa.vendor.Hibernat eJpaVendorAdapter"> 
    <property name="databasePlatform" value="${dialect}" /> 
    <property name="showSql" value="${show_sql}" /> 
    <property name="generateDdl" value="false" /> 
    </bean> 

<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionM anager"> 
<property name="entityManagerFactory" ref="entityManagerFactory" /> 
</bean> 

<bean class="org.springframework.orm.jpa.support.Persist enceAnnotationBeanPostProcessor" /> 
<bean class="org.springframework.dao.annotation.Persiste nceExceptionTranslationPostProcessor"/> 
</beans> 

一些网站建议使用UserCredintialDataSource，但它不工作实际上我想刷新的EntityManagerFactory因此它可以用在我目前的情况下，新的连接，同时获取它给人的错误无法打开连接使得实体对象数据。 谢谢

Answer 1

该EntityManagerFactory是全球性的，所以你提出的将不会工作得很好。如果刷新（即重新创建）EnitytManagerFactory，那将影响整个应用程序，而不仅仅是当前的请求/线程/用户。如果你真的想为每个用户拥有不同的数据库证书，Hibernate并不是你的最佳选择。你基本上必须为每个会话创建一个唯一的EntityManagerFactory，这会产生大量的性能开销和内存重复。你也不能使用连接池，因为你需要为每个用户打开一个新的连接。

我的建议，重新考虑你的要求和你的架构。如果您无法摆脱数据库中的用户凭证，并且必须使用Hibernate，那么您需要为每个用户会话打开和关闭新的实体管理员因素，因此必须在性能，内存和复杂性方面取得显着成效。